1. Field of Invention
This invention provides a means for dentists to shape portions of restorative materials when filling a tooth cavity, specifically, to form anatomically and functionally realistic contours and to influence the direction of contraction when photo-reactive restoratives are cured within a cavity. The means consists of ports and light reflective panels in the flanges of shims to permit lateral illumination. Embodiments include dimples, marks or notches to clearly indicate the edge nearest to the occlusal, biting, surface of the affected tooth.
2. Description of Prior Art
In the course of restoring a tooth damaged by decay a dentist will enucleate the defective tissues and refill the resultant void with prosthetic materials. In their original fluid state the restorative material may flow or sag and thereby fail to restore natural tooth anatomy. Dentists have met that problem by wrapping a thin band, usually steel, around the prepared tooth to temporarily provide a form to contain the restorative in a controlled position until it has solidified. Such bands are referred to as xe2x80x9cmatricesxe2x80x9d.
Many restoratives used are photo-reactive polymers known as xe2x80x9ccompositesxe2x80x9d. Composites may be stimulated to polymerize and become solid by projecting light upon and into the fluid mass. There is a shrinkage of volume to be expected with polymerization. It is desirable that the restorative shrink toward the residual tissues to preclude openings and leakage at the composite-to-tissue interface. The ports disclosed in this invention provide the dentists with new options for directing a light beam and thereby, for influencing the direction of shrinkage.
Teeth tend to be globular in their zones near the occlusal surfaces and conical or cylindrical near their roots, their gingival zone. The disclosed matrices are formed with an impressed dome in its occlusal areas and a cylindrical form in the gingival zone. The occlusal edge of the matrix is identified by a dimple, notch or imprint.
Various forms have been suggested for matrices. As examples, U.S. Pat. No. 1,255,109 to Russ (1918) describes a metal strip having flanges at one end which may be folded over the other end to girdle the circumference of a tooth. It is opaque and precludes any introduction of light in a horizontal plane. Further, its cylindrical conformation tends to be rigid and to resist the dentist""s efforts to reshape the form.
U.S. Pat. No. 2,310,448 to Lieb (1943) describes a thermoplastic ribbon to be wrapped around a tooth. It does not provide the malleability needed to allow the dentist to reshape its form.
U.S. Pat. No. 2,594,367 to Tofflemire (1952) shows a girdling ribbon with an aperture on its lateral aspect designed to permit an injection of restorative into a cheekside cavity. It does not offer the form or adaptability needed to recreate natural contours on the abutment surfaces nor does it permit horizontal light transmission.
U.S. Pat. No. 3,411,214 to Lazarus (1968) consists of a flattened metal loop encircling the tooth. It does not provide for lateral applications of light nor does it provide the malleability required.
U.S. Pat. No. 5,330,353 to Wavrin (1994) discloses an assembly of a plastic central portion with two metal flanges affixed laterally. It is retained around the tooth by a metal vise which interferes with horizontal light projections. It does not provide natural contours nor does it offer malleability to permit modeling in situ.
U.S. Pat. No. 5,380,198 to Suhonen (1995) describes a matrix having a metal veneer over a plastic base. It does not provide natural contours, requires a vise which limits the horizontal application of light and fails to provide for remodeling.
U.S. Pat. No. 5,788,487 to Meyer (1998) discloses a segmental matrix which does not impose upon untreated approximating surfaces and provides an impressed dome for natural contours but its opaque flanges do not permit a horizontal application of light.
Accordingly, several objects and advantages of my invention are:
1. to provide a means and form which will enable an effective reproduction of tooth contours which are natural and functional;
2. to provide a matrix which permits applications of light to the tooth and restorative in horizontal planes;
3. to provide a segmental matrix which is sufficiently malleable to permit secondary adjustments of the shape of the cavity; and;
4. to provide a segmental matrix with a marked and clearly identifiable occlusal edge. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.